from django.http import Http404, HttpResponse
from django.shortcuts import get_object_or_404
from django.utils.translation import gettext_lazy as _
from django_rq.queues import get_redis_connection
from django_rq.settings import QUEUES_LIST
from django_rq.utils import get_statistics
from drf_spectacular.types import OpenApiTypes
from drf_spectacular.utils import OpenApiParameter, extend_schema
from rest_framework import viewsets
from rest_framework.decorators import action
from rest_framework.exceptions import PermissionDenied
from rest_framework.response import Response
from rest_framework.routers import APIRootView
from rest_framework.viewsets import ReadOnlyModelViewSet
from rq.job import Job as RQ_Job
from rq.worker import Worker

from core import filtersets
from core.jobs import SyncDataSourceJob
from core.models import *
from core.utils import delete_rq_job, enqueue_rq_job, get_rq_jobs, requeue_rq_job, stop_rq_job
from netbox.api.authentication import IsAuthenticatedOrLoginNotRequired
from netbox.api.metadata import ContentTypeMetadata
from netbox.api.pagination import LimitOffsetListPagination
from netbox.api.viewsets import NetBoxModelViewSet, NetBoxReadOnlyModelViewSet
from utilities.api import IsSuperuser
from . import serializers


class CoreRootView(APIRootView):
    """
    Core API root view
    """
    def get_view_name(self):
        return 'Core'


class DataSourceViewSet(NetBoxModelViewSet):
    queryset = DataSource.objects.all()
    serializer_class = serializers.DataSourceSerializer
    filterset_class = filtersets.DataSourceFilterSet

    @action(detail=True, methods=['post'])
    def sync(self, request, pk):
        """
        Enqueue a job to synchronize the DataSource.
        """
        datasource = get_object_or_404(DataSource, pk=pk)

        if not request.user.has_perm('core.sync_datasource', obj=datasource):
            raise PermissionDenied(_("This user does not have permission to synchronize this data source."))

        # Enqueue the sync job
        SyncDataSourceJob.enqueue(instance=datasource, user=request.user)

        serializer = serializers.DataSourceSerializer(datasource, context={'request': request})

        return Response(serializer.data)


class DataFileViewSet(NetBoxReadOnlyModelViewSet):
    queryset = DataFile.objects.defer('data')
    serializer_class = serializers.DataFileSerializer
    filterset_class = filtersets.DataFileFilterSet


class JobViewSet(ReadOnlyModelViewSet):
    """
    Retrieve a list of job results
    """
    queryset = Job.objects.all()
    serializer_class = serializers.JobSerializer
    filterset_class = filtersets.JobFilterSet


class ObjectChangeViewSet(ReadOnlyModelViewSet):
    """
    Retrieve a list of recent changes.
    """
    metadata_class = ContentTypeMetadata
    serializer_class = serializers.ObjectChangeSerializer
    filterset_class = filtersets.ObjectChangeFilterSet

    def get_queryset(self):
        return ObjectChange.objects.valid_models()


class ObjectTypeViewSet(ReadOnlyModelViewSet):
    """
    Read-only list of ObjectTypes.
    """
    permission_classes = [IsAuthenticatedOrLoginNotRequired]
    queryset = ObjectType.objects.order_by('app_label', 'model')
    serializer_class = serializers.ObjectTypeSerializer
    filterset_class = filtersets.ObjectTypeFilterSet


class BaseRQViewSet(viewsets.ViewSet):
    """
    Base class for RQ view sets. Provides a list() method. Subclasses must implement get_data().
    """
    permission_classes = [IsSuperuser]
    serializer_class = None

    def get_data(self):
        raise NotImplementedError()

    @extend_schema(responses={200: OpenApiTypes.OBJECT})
    def list(self, request):
        data = self.get_data()
        paginator = LimitOffsetListPagination()
        data = paginator.paginate_list(data, request)

        serializer = self.serializer_class(data, many=True, context={'request': request})
        return paginator.get_paginated_response(serializer.data)

    def get_serializer(self, *args, **kwargs):
        """
        Return the serializer instance that should be used for validating and
        deserializing input and for serializing output.
        """
        serializer_class = self.get_serializer_class()
        kwargs['context'] = self.get_serializer_context()
        return serializer_class(*args, **kwargs)

    def get_serializer_class(self):
        """
        Return the class to use for the serializer.
        """
        return self.serializer_class

    def get_serializer_context(self):
        """
        Extra context provided to the serializer class.
        """
        return {
            'request': self.request,
            'format': self.format_kwarg,
            'view': self,
        }


class BackgroundQueueViewSet(BaseRQViewSet):
    """
    Retrieve a list of RQ Queues.
    Note: Queue names are not URL safe, so not returning a detail view.
    """
    serializer_class = serializers.BackgroundQueueSerializer
    lookup_field = 'name'
    lookup_value_regex = r'[\w.@+-]+'

    def get_view_name(self):
        return 'Background Queues'

    def get_data(self):
        return get_statistics(run_maintenance_tasks=True)['queues']

    @extend_schema(
        operation_id='core_background_queues_retrieve_by_name',
        parameters=[OpenApiParameter(name='name', type=OpenApiTypes.STR, location=OpenApiParameter.PATH)],
        responses={200: OpenApiTypes.OBJECT},
    )
    def retrieve(self, request, name):
        data = self.get_data()
        if not data:
            raise Http404

        for queue in data:
            if queue['name'] == name:
                serializer = self.serializer_class(queue, context={'request': request})
                return Response(serializer.data)

        raise Http404


class BackgroundWorkerViewSet(BaseRQViewSet):
    """
    Retrieve a list of RQ Workers.
    """
    serializer_class = serializers.BackgroundWorkerSerializer
    lookup_field = 'name'

    def get_view_name(self):
        return 'Background Workers'

    def get_data(self):
        config = QUEUES_LIST[0]
        return Worker.all(get_redis_connection(config['connection_config']))

    @extend_schema(
        operation_id='core_background_workers_retrieve_by_name',
        parameters=[OpenApiParameter(name='name', type=OpenApiTypes.STR, location=OpenApiParameter.PATH)],
        responses={200: OpenApiTypes.OBJECT},
    )
    def retrieve(self, request, name):
        # all the RQ queues should use the same connection
        config = QUEUES_LIST[0]
        workers = Worker.all(get_redis_connection(config['connection_config']))
        worker = next((item for item in workers if item.name == name), None)
        if not worker:
            raise Http404

        serializer = serializers.BackgroundWorkerSerializer(worker, context={'request': request})
        return Response(serializer.data)


class BackgroundTaskViewSet(BaseRQViewSet):
    """
    Retrieve a list of RQ Tasks.
    """
    serializer_class = serializers.BackgroundTaskSerializer
    lookup_field = 'id'

    def get_view_name(self):
        return 'Background Tasks'

    def get_data(self):
        return get_rq_jobs()

    def get_task_from_id(self, task_id):
        config = QUEUES_LIST[0]
        task = RQ_Job.fetch(task_id, connection=get_redis_connection(config['connection_config']))
        if not task:
            raise Http404

        return task

    @extend_schema(
        operation_id='core_background_tasks_retrieve_by_id',
        parameters=[OpenApiParameter(name='id', type=OpenApiTypes.STR, location=OpenApiParameter.PATH)],
        responses={200: OpenApiTypes.OBJECT},
    )
    def retrieve(self, request, id):
        """
        Retrieve the details of the specified RQ Task.
        """
        task = self.get_task_from_id(id)
        serializer = self.serializer_class(task, context={'request': request})
        return Response(serializer.data)

    @extend_schema(parameters=[OpenApiParameter(name='id', type=OpenApiTypes.STR, location=OpenApiParameter.PATH)])
    @action(methods=['POST'], detail=True)
    def delete(self, request, id):
        """
        Delete the specified RQ Task.
        """
        delete_rq_job(id)
        return HttpResponse(status=200)

    @extend_schema(parameters=[OpenApiParameter(name='id', type=OpenApiTypes.STR, location=OpenApiParameter.PATH)])
    @action(methods=['POST'], detail=True)
    def requeue(self, request, id):
        """
        Requeues the specified RQ Task.
        """
        requeue_rq_job(id)
        return HttpResponse(status=200)

    @extend_schema(parameters=[OpenApiParameter(name='id', type=OpenApiTypes.STR, location=OpenApiParameter.PATH)])
    @action(methods=['POST'], detail=True)
    def enqueue(self, request, id):
        """
        Enqueues the specified RQ Task.
        """
        enqueue_rq_job(id)
        return HttpResponse(status=200)

    @extend_schema(parameters=[OpenApiParameter(name='id', type=OpenApiTypes.STR, location=OpenApiParameter.PATH)])
    @action(methods=['POST'], detail=True)
    def stop(self, request, id):
        """
        Stops the specified RQ Task.
        """
        stopped_jobs = stop_rq_job(id)
        if len(stopped_jobs) == 1:
            return HttpResponse(status=200)
        else:
            return HttpResponse(status=204)